Aperiodic Alternate Characteristic Series

SPECIES

Alternate characteristic series of natural numbers (starting from 1)

\displaystyle \sum_{n\geq1} (-1)^{n-1} \chi(n) = \displaystyle \sum_{n\geq1} (-1)^{n-1} = 1-1+1-1+1-1\pm\cdots = \dfrac{1}{2}   (stable)